Fishing lures having a primary hook and a spring-loaded secondary hook have been used in the past. Examples of such fishing lures are disclosed in U.S. Pat. No. 4,670 issued Jul. 28, 1846 to Engelbrecht et al. This patent discloses a primary hook for a fish to engage and a secondary hook pivotally connected to the first hook. The secondary hook is held in an open cocked position by a trip mechanism connected to a fishing line. In operation, the fish would engage the primary hook and increase the tension on the line connected to the trip mechanism to disengage the secondary hook for engaging the fish to prevent escape.
Other examples of such fishing lures are disclosed in U.S. Pat. No. 2,149,923, issued Mar. 7, 1939 to Martin; U.S. Pat. No. 3,618,251, issued Nov. 9, 1971 to Hodshire; and U.S. Pat. No. 4,638,591, issued Jan. 27, 1987 to Neumann et al.
The problem with the above fishing lures is that no means is provided for adjustably predetermining the amount of pulling force required to release the trip mechanism. Further, the pulling force device is not removably attached to the fishing lure to allow the pulling force to be varied or adjusted to different predetermined levels.